1. Field of the Invention
This invention relates to devices useful for leveling parked recreational vehicles and trailers when positioned on an angled surface. The present invention is particularly directed towards a device utilizing two stacked interlocking blocks employed as drive-over wheel height adjusters for tandem wheeled trailers.
2. Description of the Prior Art
When parking certain vehicles, especially recreational trailers, it is often necessary for the vehicle to be level in order for certain appliances, such as refrigerators, to work correctly. It is also more comfortable for the user to sleep in a level position. One very efficient method of leveling vehicles includes the use of mechanical hydraulic or pneumatic jacks. Unfortunately these devices are quite expensive and unless they are attached to the vehicle when manufactured, major alterations are needed to install such devices to existing vehicles.
The majority of recreational trailer owners choose parking sites which are substantially level to begin with and usually only minor adjustments of a few inches are required to level the vehicle. These owners also generally prefer a leveling device which is quick and easy to use and requires little of the already limited available space to storage.
A search was conducted for patented devices useful for leveling vehicles. These past art patents were obtained from the following classes and subclasses;
280/6R, 6.11, 180/41, 188/32, 254/94 and 88.
The past art devices which I considered most pertinent to my invention are as follows:
1. U.S. Pat. No. 3,661,229, dated May 9, 1972, was issued to Stonhaus for a leveling device comprised of two inclined ramps.
2. Breen was granted U.S. Pat. No. 4,034,961, dated July 12, 1977 for "Drive-On Leveling Device" containing two curved ramps.
3. On Nov. 15, 1977, Goodrich et al was issued U.S. Pat. No. 4,058,292 for a leveling system using inclined ramps designed to be attached to the vehicle by linking means. This linking means provides coded indicia indicating the required distance the wheels need to travel to level the vehicle.
4. Bennett was granted U.S. Pat. No. 4,165,862 on Aug. 28, 1979 for a leveling device comprised of vertically stacked inclined slabs.
5. U.S. Pat. No. 4,427,179, dated Jan. 24, 1984, was issued to Price for a leveling apparatus comprised of a plurality of ramp planks.
The past art patent which seems closest in proximity to my device is U.S. Pat. No. 4,165,862. Although ramp style leveling devices are necessarily somewhat similar, this device contains significant disadvantages not present in my device. The Bennett ramp is not designed to be driven completely over. A driver can approach the ramp from only one direction to properly position his wheels on top.
The remaining aforementioned patents also teach devices which are not designed to be completely driven over and therefore can be approached by the wheel for use in only one direction. There are instances when the capability to drive completely over the ramp is more convenient, such as if the driver accidentally misjudges the distance and over shoots the ends of the ramps. Using one of the devices shown in the past art, the driver would have to get out of the towing vehicle and replace each ramp in front of each tire and try the procedure again. In a trailer having tandem wheels, the driver would have to move up to four leveling devices.
Past art patent U.S. Pat. No. 4,058,292 teaches a device which provides for a wide variation of height adjustments, which I feel is unnecessary. Height adjustments over four to six inches are seldom required by recreational trailer users, due to the fact most commercial and government trailer camp sites are substantially level to begin with. This device appears very large and would require a great amount of storage area. Also, it would not fit between the typical tandem wheels of a recreational trailer.
Past art patents including U.S. Pat. Nos. 3,661,229, 4,034,961, and 4,058,292 do not provide level surfaces for the parked tire. This situation appears to pose a potential rolling problem and would require the use of additional blocking means. Two of the devices do provide leveling structures with an additional blocking means. These additional wheel blocking devices require added time and effort to position, and put the installer's hand at risk of being smashed if the trailer slipped forward before he could get the wheel blocked.
The afore mentioned patents represented devices which appear most relevant to my invention. They do not seem to illustrate the advantages and benefits provided by my invention, particularly for use in fairly level camp sites. Most of the past art devices disclosed jacking systems and interlocking multi-step wheel blocks difficult to use. My invention eliminates the mechanical actions of jacks and the use of complicated curved surfaces in a simple drive-on and drive-over block structure easy to position and safe to use.